This invention relates to measurement of permittivity and permeability of different materials, and more particularly to measurement of these properties in radar absorber materials at microwave and millimeter frequencies.
The application of radar absorber materials for concealment of aircraft and missiles hinges on a knowledge of the intrinsic properties of complex permittivity (epsilon) and permeability (mu) of the materials over a wide frequency range. These two properties are a measure of the abilities to conduct electric and magnetic fields which are present in the radar environments. The design and test of the materials depends on the capability to accurately measure the properties. Traditionally, such measurements have been made at fixed frequencies below 10 GHz using slotted-line and impedance-bridge configurations.